System and method for overhead cross-system transportation

ABSTRACT

A system for managing semiconductor production includes a conveyor to convey a wafer carrier to or from an overhead hoist transfer system. The system also includes a cross-system transport apparatus to transfer the wafer carrier between the conveyor and an overhead shuttle system.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of U.S. Provisional PatentApplication Ser. No. 61/256,120, filed on Oct. 29, 2009, which isincorporated herein by reference in its entirety.

BACKGROUND

In modern semiconductor fabrication facilities, overhead shuttle (OHS)systems and overhead hoist transport (OHT) systems are extensively usedto automate the wafer transport process. The OHS is a transportmechanism suitable for long distance interbay transport and the OHT issuitable for short distance intrabay transport. Based on dispatchingneed and by the instruction of an automated material handling system(AMHS), a stocker can store wafer carriers for the OHS and the OHTbefore the wafer carriers are further transported. A wafer carrier maymove within the same transport system, or the wafer carrier may berouted from the OHS to the OHT or vice versa. For cross-systemtransportation between the OHS and the OHT, a robot inside the stockeris configured to transfer the wafer carrier from one transport system tothe other.

Although the robot inside the stocker performs cross-systemtransportation between the OHS and the OHT, the robot is also used totransfer wafer carriers between the stocker and either the OHS or theOHT if the movement of wafer carriers is within the same transportsystem. The robot inside the stocker serves both the needs ofsingle-system transportation and cross-system transportation. Therefore,the robot may be overloaded and cause traffic congestion in times ofheavy traffic. In addition, regarding space utilization, the stockerwill occupy the shop floor of a semiconductor manufacturing facility forstorage of wafer carriers. The shop floor in a clean room of thesemiconductor manufacturing facility is valuable and limited.

The dual roles of the robot to facilitate the storage function of astocker for the same transport system and to perform cross-systemtransportation make the robot a potential bottleneck of the overalltransportation of wafer carriers. The stocker and the robot might notmeet the expectation of lean operation in semiconductor fabricationfacilities. In addition, if the stocker is used solely for cross-systemtransportation, the shop floor occupied by the stocker would be lesscost effective.

DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings, whereinelements having the same reference numeral designations represent likeelements throughout and wherein:

FIG. 1 is a schematic, perspective view of a cross-system transportaccording to an embodiment;

FIG. 2 is a schematic, side view of the FIG. 1 embodiment;

FIG. 3 is a schematic, perspective view of a cross-system transport forbidirectional transportation according to another embodiment;

FIG. 4 is a schematic, perspective view of a cross-system transportcomprising a slide fork according to another embodiment;

FIG. 5 is a schematic, perspective view of a cross-system transportcomprising a crane and robot arm according to another embodiment; and

FIG. 6 is a high-level functional block diagram of a controller systemaccording to an embodiment.

DETAILED DESCRIPTION

FIG. 1 depicts a view of an overhead cross-system transport 100according to an embodiment. Transport 100 includes a conveyor 110 and across-system transport apparatus (generally indicated by referencenumeral 119), and transfers a wafer carrier 102 between an overheadtransport (OHT) system 104 and an overhead shuttle (OHS) system 106.Wafer carrier 102 is a front-opening unified pod (FOUP) for carryingwafers. In at least some embodiments, wafer carrier 102 may beconfigured to transport a plurality of wafers, e.g., 6 wafers, 12wafers, 24 wafers, etc. In at least some embodiments, wafer carrier 102may comprise different FOUP sizes such as 300 millimeter (mm) or 450 mm.Other types and/or sizes of wafer carrier or pod are, however, notexcluded.

OHT 104 operates to vertically load and unload a wafer carrier to/from amaterial handling and/or a processing machine (not shown). For examplein FIG. 1, the OHT 104 has a wafer carrier 102 that is being verticallytransported to conveyor 110. The OHT 104 unloads or places the wafercarrier 102 to a loading station (generally indicated by referencenumeral 112) of the conveyor 110. In another example, OHT 104 picks thewafer carrier 102 from station 112 which, in that case, is an unloadingstation of conveyor 110.

In at least some embodiments, the OHT 104 hangs suspended from theceiling 124. OHT 104 is equipped with a gripper that can grasp the topflange of the wafer carrier 102. To transfer the wafer carrier 102 to aprocess tool, the gripper is lowered down to the load port of the tooland then places the wafer carrier 102 on the load port.

Conveyor 110 extends in a generally horizontal direction from left toright across the page. Conveyor 110 comprises first loading/unloadingstation 112 at one end and a first operating position (generallyindicated by reference numeral 114) at another end of the conveyor. Inat least some embodiments, one or the other or both of firstloading/unloading station 112 or first operating position 114 may bepositioned at a portion of conveyor 110 other than an end. Conveyor 110may be hung from ceiling 124 or another object able to support theweight of conveyor 110.

Conveyor 110 is arranged to transport wafer carrier 102 in a horizontaldirection (generally indicated by reference character A) between firstloading/unloading station 112 and first operating position 114 forinteraction with cross-system transport apparatus 119. In at least someembodiments, conveyor 110 comprises a belt-based system, e.g., aconveyor belt. In at least some other embodiments, conveyor 110comprises a transport mechanism for transporting a received wafercarrier in a horizontal direction. In at least some other embodiments,conveyor 110 comprises a transport mechanism for transporting a receivedwafer carrier in a vertical or partially vertical direction. In at leastsome other embodiments, conveyor 110 comprises a different transportmechanism such as rollers, a movable arm, etc.

Cross-system transport apparatus 119 in the specifically illustratedconfiguration includes a hoist 116 and a slide table 120. Conveyor 110conveys the wafer carrier 102 to the first operating position 114 forhoist 116 to grasp and raise the wafer carrier 102 to a second operatingposition (generally indicated by reference numeral 118) of slide table120.

The hoist 116 comprises at least one, e.g., 4, sets of belt and pulleymechanism, gripper, and motor driver that can rotate the belt and pulleymechanism to raise and lower down the gripper. In some embodiments, thegripper of hoist 116 is similar that of OHT 104 to grasp the top flangeof the wafer carrier 102. The slide table 120 comprises a set of alinear guide, a ball screw, and a motor. The slide table 120 provides atleast one degree of linear motion (forward and backward).

On the slide table 120, the hoist 116 is slideable to a secondunloading/loading station (generally indicated by reference numeral 122)and arranged to unload/load the wafer carrier 102 to/from the OHS 106.

The OHS 106 comprises a set of tracks, one or more shuttle-typevehicles, and a vehicle control system. The OHS 106 is arranged totransport a wafer carrier 102 on a stage of the vehicle. The OHS 106transports wafer carriers between stockers (from one stocker to anotherstocker). When the OHS 106 arrives at the load/unload station ofstockers, the wafer carrier 102 will be picked by the arm of stockersand stored inside the stockers.

In addition, the slide table 120 is attached to the ceiling 124 in asemiconductor manufacturing facility. In at least some embodiments,slide table 120 is suspended from the ceiling or an intermediate memberattached to the ceiling. In at least some embodiments, the cross-systemtransport 100 does not occupy any space of floor 126 in themanufacturing facility. In at least some other embodiments, thecross-system transport 100 occupies less floor space than a stocker.

FIG. 2 depicts a side view of the FIG. 1 embodiment. In operationaccording to at least one embodiment, the wafer carrier 102 is unloadedfrom OHT 104, e.g., by placement or lowering onto the conveyor 110,moved from first loading/unloading station 112 to first operatingposition 114 by the conveyor 110 (in a horizontal direction indicated byreference character A), hoisted by the hoist 116 (in a verticaldirection indicated by reference character B), then slid on the slidetable 120 from the second operating position 118 to the secondunloading/loading station 122 (in a horizontal direction indicated byreference character C) and placed on a vehicle of OHS 106. According toat least another embodiment (not shown in FIG. 2), the wafer carrier 102is transported in the opposite direction from the OHS 106 to the OHT 104in a manner similar to a cross-system transport 300 that will bedescription herein with respect to FIG. 3. In at least anotherembodiment, cross-system transport 100 is configured to selectivelytransport the wafer carrier 102 from the OHS 106 to the OHT 104 or fromthe OHT 104 to the OHS 106.

FIG. 3 depicts two-way transportation of wafer carriers between OHT 104and OHS 106 by a first cross-system transport 100 and a secondcross-system transport 300. In at least one embodiment, the movingdirection of the transport 100 is opposite to the moving direction ofthe transport 300. In at least some embodiments, the moving direction ofthe transport 100 is the same as the moving direction of the transport300. To execute a cross-system transportation from the OHS 106 to theOHT 104 through the transport 300, a wafer carrier 302 is prepared atstop station 304 of the OHS 106 for the hoist 306 to grasp the wafercarrier 302. Next, the hoist 306 along with the grasped wafer carrier302 slides on the slide table 308 in a horizontal direction E and movesthe wafer carrier 302 from loading position 310 to operating position312. The hoist 306 lowers the wafer carrier 302 in a vertical directionF to the operating position 314 on an L-shaped conveyor 316. A purposeof the conveyor in at least one embodiment is to be the bridge betweenOHT 104 and the hoist 306 and, in some embodiments, to provide abuffering function. The L-shaped conveyor 316 is exemplary. The shapeand height of the conveyor depends on the load/unload locations of OHT104 and the location of the hoist 306. By using different conveyorbelts, conveyor 316 moves the wafer carrier 302 in a horizontaldirection G1 and rotates the wafer carrier 302 to a different directionG2, in at least some embodiments. The wafer carrier 302 is transportedto loading position 318 for the OHT 104 to pick up and transfer thewafer carrier 302 to the appropriate handling or processing machine.Similar to transport 100 in at least some embodiments, the transport 300does not occupy any space of floor 126 in the manufacturing facility.

FIG. 4 depicts an overhead cross-system transport 400 according toanother embodiment which comprises a slide fork 401 as part of itscross-system transport apparatus. The slide fork 401 includes a firstslide table 402 (also referred to as an upper slide table) and a secondslide table 404 (also referred to as a lower slide table). The firstslide table 402 is attached to the ceiling 124 in a manufacturingfacility and the second slide table 404 is slidably coupled with thefirst table 402. In at least some embodiments, first and second slidetables 402, 404 are coupled to be slideable with respect to each otherin at least one direction. In at least some embodiments, first slidetable 402 is attached to a device or mount positioned above OHS 106.

A hoist 406, similar to hoist 116, is attached to the second slide table404 at a lower face of the second table (as indicated by reference arrow408). During a sliding movement of the second slide table 404, theattached hoist 406 moves a grasped wafer carrier 412 horizontallybetween an OHS load/unload position 409 and a raise/lower position 410.At load/unload position 409, the hoist 406 alternately unloads the wafercarrier 412 to the OHS 106 or grasps and loads, by a gripper (not shown)similar to that of hoist 116, the wafer carrier 412 from the OHS 106 toslide fork 401. At raise/lower position 410, the hoist 406 lowers thewafer carrier 412 to the conveyor 110 or grasps the wafer carrier 412from the conveyor 110. The slide fork 401 changes the horizontalmovement of the hoist 406 without impacting the vertical operation ofthe cross-system transport 400. In at least some embodiments, thetransport 400 does not occupy any floor space in the manufacturingfacility. In at least some embodiments, the transport 400 minimizes theuse of floor space in the manufacturing facility for cross-systemtransport.

FIG. 5 depicts a cross-system transport 500 comprising, as itscross-system transport apparatus, a crane 502 and a robot arm 504,according to another embodiment. The robot arm 504 is arranged to graspa wafer carrier 506 from the OHS 106 or from the conveyor 110.Conversely, the robot arm 504 can unload the wafer carrier 506 to theOHS 106 or to the conveyor 110. In some embodiments, a clamp (not shown)is provided on the robot arm 504 to clasp the wafer carrier by thebottom surface of the wafer carrier as illustrated in FIG. 5. The robotarm 504 is attached to the crane 502 and movable vertically along thecrane. Responsive to a request for a cross-system transportation, suchas for transport of a wafer carrier from the OHS 106 to the OHT 104, therobot arm 504 grasps the wafer carrier 506 from a load/unload position508 (similar to load/unload position 409 (FIG. 4)), moves the wafercarrier 506 in a horizontal direction H to a raise/lower position 510(similar to raise/lower position 410 (FIG. 4)), lowers the wafer carrier506 in a vertical direction J to a conveyor load/unload position 512,then moves the wafer carrier 506 in another horizontal direction K andunloads the wafer carrier 506 to the conveyor 110 for further transportas described above.

FIG. 6 depicts a high-level block diagram of a controller system 600(also referred to as a controller) in accordance with an embodiment.Controller 600 generates output control signals for controllingoperation of one or more components of one or more cross-systemtransport such as 100, 300, 400, 500 in accordance with at least oneembodiment (only cross-system transport 100 is shown in FIG. 6 forillustrative purposes). Controller 600 receives input signals from oneor more components (e.g., conveyor 110 and/or cross-system transportapparatus 119) of cross-system transport 100 and/or OHS 106 and/or OHT104 and/or an automated material handling system (AMHS) in accordancewith at least one embodiment. In at least some embodiments, controllersystem 600 is located adjacent cross-system transport 100. In at leastsome further embodiments, controller system 600 is integrated as acomponent of cross-system transport 100. In at least some otherembodiments, controller system 600 is remote from cross-system transport100.

Controller system 600 comprises a processor 602, an input/output (I/O)device 604, a memory 606, and a network interface (I/F) 608 eachcommunicatively coupled via a bus 610 or other interconnectioncommunication mechanism.

Processor 602 may comprise a processor, a microprocessor, a controller,or other device such as an application-specific integrated circuit(ASIC) arranged to execute and/or interpret one or more sets ofinstructions, e.g., a transport control system 612 stored in memory 606.

I/O device 604 may comprise an input device, an output device, and/or acombined input/output device for enabling user interaction. An inputdevice may comprise a mechanism for communicating at least a command toprocessor 602. In at least some embodiments, input/output device 604 maycomprise a serial and/or parallel connection mechanism.

Memory 606 (also referred to as a computer-readable medium) may comprisea random access memory or other dynamic storage device, communicativelycoupled to bus 610 for storing data and/or instructions for execution byprocessor 602. Memory 606 also may be used for storing temporaryvariables or other intermediate information during execution ofinstructions to be executed by processor 602. Memory 606 may alsocomprise a read-only memory or other static storage device coupled tothe bus 610 for storing static information and instructions forprocessor 602.

Memory 606 stores a transport control system 612 (a set of executableinstructions) for controlling one or more components of cross-systemtransport 100. In some other embodiments, the transport control system612 is implemented as a hard-wired circuit and integrated into theprocessor 602.

Network interface 608 comprises a mechanism for connecting to a network.In at least some embodiments, network interface 608 may comprise a wiredand/or wireless connection mechanism. In at least some embodiments,controller system 600 is coupled with one or more components ofcross-system transport 100 via network interface 608, as depicted. In atleast some other embodiments, controller system 600 is directly coupledwith one or more components of cross-system transport 100, e.g., withthe components coupled to bus 610 instead of via network interface 608.

It will be readily seen by one of ordinary skill in the art that thedisclosed embodiments fulfill one or more of the advantages set forthabove. After reading the foregoing specification, one of ordinary skillwill be able to affect various changes, substitutions of equivalents andvarious other embodiments as broadly disclosed herein. It is thereforeintended that the protection granted hereon be limited only by thedefinition contained in the appended claims and equivalents thereof.

What is claimed is:
 1. A system for managing semiconductor production,the system comprising: a conveyor to convey a wafer carrier to or froman overhead hoist transfer (OHT) system; a cross-system transportapparatus to transfer the wafer carrier between the conveyor and anoverhead shuttle (OHS) system; and a controller configured to outputcontrol signals to control at least one of the cross-system transportapparatus, the conveyor, and the loading or unloading of the wafercarrier at the OHT or the OHS, wherein the cross-system transportapparatus comprises a lifting device configured to raise or lower thewafer carrier.
 2. The system according to claim 1, wherein thecross-system transport apparatus occupies zero floor space within asemiconductor manufacturing facility.
 3. The system according to claim1, wherein the cross-system transport apparatus further comprises: anoverhead transport, and the lifting device comprises: a hoist coupled toand moveable along the overhead transport, the hoist being configured toraise or lower the wafer carrier between the conveyor and the overheadtransport and the hoist being configured to grip and release the wafercarrier located at the conveyor or at the OHS.
 4. The system accordingto claim 3, wherein said wafer carrier has a top flange adapted to beclasped by the OHT and wherein the hoist is also configured to claspsaid wafer carrier by the top flange.
 5. The system according to claim1, wherein the cross-system transport apparatus further comprises: anupper slide table; and a lower slide table coupled to and slidablerelative to the upper slide table to define a slide fork; and thelifting device comprises: a hoist attached to the lower slide table ofthe slide fork, the hoist being configured to raise or lower the wafercarrier between the conveyor and the OHS via movements of the slide forkand the hoist being configured to grip and release the wafer carrierlocated at the conveyor or at the OHS.
 6. The system according to claim5, wherein said wafer carrier has a top flange adapted to be clasped bysaid OHT and wherein the hoist is also configured to clasp said wafercarrier by the top flange.
 7. The system according to claim 1, whereinthe lifting device comprises a crane, and the cross-system transportapparatus further comprises: a robot arm slidably coupled to the crane;the robot arm being configured to move the wafer carrier between theconveyor and the OHS.
 8. The system according to claim 7, wherein therobot arm is configured to clamp onto the wafer carrier.
 9. The systemaccording to claim 8, wherein said wafer carrier has a bottom surface,and said robot arm is configured to clasp the wafer carrier by thebottom surface.
 10. The system according to claim 1, further comprisingthe wafer carrier being a front-opening unified pod (FOUP).
 11. Thesystem according to claim 1, wherein the conveyor defines an area forbuffering one or more said wafer carrier.
 12. The system according toclaim 1, wherein the conveyor is configured to rotate said wafer carrierto a different conveying direction.
 13. The system according to claim 1,wherein the controller is configured to receive at least onetransportation request of said wafer carrier from an automated materialhandling system (AMHS).
 14. The system for managing semiconductorproduction of claim 1, wherein the OHS system has tracks.
 15. The systemfor managing semiconductor production of claim 14, wherein the OHSfurther comprises at least one shuttle-type vehicle adapted to travel onthe tracks.
 16. The system for managing semiconductor production ofclaim 15, wherein the OHS further comprises a vehicle control systemadapted to control the at least one shuttle-type vehicle.
 17. The systemfor managing semiconductor production of claim 16, wherein the at leastone shuttle-type vehicle further comprises a stage adapted to transportthe wafer carrier.
 18. A system for managing semiconductor production,the system comprising: a conveyor configured to move a wafer carrier toor from an overhead hoist transfer (OHT) system; and an overheadtransfer apparatus comprising a lifting device configured to transfersaid wafer carrier in at least an elevational manner between saidconveyor and an overhead shuttle (OHS) system.
 19. The system accordingto claim 18, where said overhead transfer apparatus includes a gripperconfigured to grab said wafer carrier.
 20. The system according to claim18, further comprising: a slide table configured to transfer said wafercarrier to or from said OHS.
 21. A system for managing semiconductorproduction, the system comprising: a conveyor to convey a wafer carrierto or from an overhead hoist transfer (OHT) system; an overhead shuttle(OHS) system having tracks; a cross-system transport apparatus totransfer the wafer carrier between the conveyor and the OHS system; anda controller configured to output control signals to control at leastone of the cross-system transport apparatus, the conveyor, and theloading or unloading of the wafer carrier at the OHT or the OHS, whereinthe cross-system transport apparatus comprises a gripper configured tograb a top portion of the wafer carrier.
 22. The system for managingsemiconductor production of claim 21, wherein the OHS further comprisesat least one shuttle-type vehicle adapted to travel on the tracks. 23.The system for managing semiconductor production of claim 22, whereinthe OHS further comprises a vehicle control system adapted to controlthe at least one shuttle-type vehicle.
 24. The system for managingsemiconductor production of claim 23, wherein the at least oneshuttle-type vehicle further comprises a stage adapted to transport thewafer carrier.